In many developed nations, diseases attributable to type I allergic reactions such as pollinosis (hay fever), bronchial asthma or atopic dermatitis are on the increase and becoming a social problem.
Among 5 kinds of antibodies possessed by humans, an antibody called IgE is involved particularly in type I allergic reaction, and this antibody tends to be produced in a larger amount in persons with an allergic constitution than in healthy persons without an allergic constitution. Production of IgE is promoted by interleukin 4 (IL-4) or interleukin 13 (IL-13) derived form type 2 helper T lymphocyte (Th2), and is reported in recent years to be inhibited by interleukin 2 (IL-2) or interferon γ (IFN-γ) derived from type I helper T lymphocyte (Th1). For ameliorating the allergic constitution, therefore, it is important to inhibit production of IgE by inhibiting the production of IL-4 or IL-13 or by promoting the production of IL-2 or IFN-γ. In addition, TNF (tumor necrosis factor) is also involved in type I allergic reaction and thus inhibition of TNF production is also effective in inhibiting inflammatory reactions.
For ameliorating diseases by the above type I allergic reaction, pharmaceutical preparations such as antihistamines, anti-allergic agents and steroids have been developed and used so far. These chemicals may be accompanied by side effects such as worsening of morbid state due to long-term administration (rebound phenomenon), sleepiness by their action on the central nerves, their influence on the internal secretory system by transdermal absorption, etc.
For the purpose of ameliorating the diseases safely without side effects, on the other hand, foods having an anti-allergic action have been searched for from conventionally eaten foods (see JP-A No. 61-291524, JP-A No. 1-121217, JP-A No. 7-215884 etc.). Further, previously marketed and widely recognized drinks include a sweet tea extract made from leaves of Rubus Suavissimus with hot water and a beefsteak plant extract made from a beef steak plant (Perilla frutescens) with hot water. Also, lactic acid bacteria have an action of inducing Th1 cells from the viewpoint of probiotics and are thus examined as anti-allergic material.
However, a majority of compounds used as pharmaceutical preparations are problematic because of the side effects mentioned above. There are also food-derived anti-allergic materials such as a sweet tea extract and a beefsteak plant leaf extract, but from the viewpoint of different working mechanisms, greater efficacy and/or economical advantage, there is a need for utilizing anti-allergic materials derived from other foods. The anti-allergic action of lactic acid bacteria is problematic due to the low action of lactic acid bacteria when used on its own.